Video-based driver assistance systems, which display images recorded by a camera on a display, are used for assisting the drivers of motor vehicles. In this manner it is possible, for example, to assist the driver in detecting parking space boundaries or obstacles using a backup camera system when reverse parking. By using infrared-sensitive image sensors, as described in International Application No. WO 2004/047449 A1 for example, the driver may also be effectively assisted in connection with so-called night view systems even in conditions of poor visibility or poor weather conditions. An “automotive infrared night vision device” is also described in International Application No. WO 2003/064213 A1, which selectively displays a processed camera image of the area in front of the driver.
In order to assist the driver even further in such assistance systems, additional information is generated or retrieved and additionally drawn into the images recorded by the image sensor unit and displayed in the display unit. Thus, for example in a night view system having integrated lane detection, the lane of the vehicle or, in a backup camera system, assister lines for facilitating the parking process may be visually displayed as additional information in the display unit. Symbols or texts may also be generated and displayed as additional information. For this purpose, artificially generated graphical data are represented in the display unit together with the recorded images of the actual surrounding of the vehicle. A display or monitor may be preferably used as a display unit.
A method and system for displaying at least one navigational instruction are described in German Patent Application No. DE 101 38 719 A1. In this instance, navigation instructions are inserted into the images of the vehicle's surroundings that were recorded by a vehicle camera and represented in the display unit. The document also teaches to take the inclination of the vehicle along the longitudinal and lateral axis into account when generating the display.
Moreover, Japanese Patent No. JP 11023305 A1 describes that obstacles, which may exist in the form of stationary or moving objects as other vehicles for example, have inserted navigation instructions transparently superposed, rather than being covered by them.
Furthermore, Japanese Patent Documents JP 09325042 A1 and JP 2004257979 A1 also describe methods in which navigation instructions are displayed in a display unit, the distance of vehicle position and destination position being respectively taken into account for generating the display.
Thus, Japanese Patent Application JP 09325042 A1 describes, for example, inserting navigation arrows into an image recorded by a video camera, turn-off arrows being adjusted in their length to the distance to the turn-off point.
Japanese Patent Application No. JP 2004257979 A1 describes the insertion of turn-off instructions into a recorded image when the distance between the current vehicle position and the turn-off point is smaller than or equal to a specific value.
Navigation instructions inserted into displays are generally used to relieve the driver in complicated traffic situations and to help him generally achieve a better orientation. The advantages of navigation instructions are revealed particularly clearly when side streets follow one upon another closely in fast moving traffic.
The display unit in the form of a display integrated into a navigation device or a separate, usually smaller display situated in the cockpit of the vehicle normally presents navigation instructions in the form of arrows that are displayed statically. Navigation instructions may also be represented in a different form, however, as guiding beacons, warning beacons, direction beacons in curves, guide pole symbols or as traffic signs, for example.